In a nucleophilic substitution reaction, unreacted electrophile must be removed from the reaction mixture prior to any subsequent reactions. Otherwise, unreacted electrophile will compete with the subsequent reactions resulting in the formation of undesired compounds.
Nucleophilic substitution reactions are well known per se and are described in Advanced Organic Chemistry, 4th ed., Jerry March, John Wiley & Sons, New York, N.Y., 1992, which is incorporated herein by reference. Typically, such reactions use an excess of reagent, often electrophile, and the excess or unreacted electrophile is removed by distillation, crystallization, chromatography, high pressure liquid chromatography (HPLC), medium pressure liquid chromatography (MPLC) or a combination thereof, before other nucleophilic substitution or other reactions are carded out. These traditional methods are generally labor intensive and can require many hours to effectively remove the excess electrophile.
When multiple nucleophilic substitution reactions are to be carried out, for example in a solution phase synthesis, it is evident that the removal of excess electrophile can utilize large amounts of time and be quite costly. Therefore, there is a great need for a simple, efficient and effective method for scavenging electrophiles from a reaction mixture.